search for: fahrmeir

How might you fit a generalized linear model (glm) with variance = mu+theta*mu^2 (where mu = mean of the exponential family random variable and theta is a parameter to be estimated)? This appears in Table 2.7 of Fahrmeir and Tutz (2001) Multivariate Statisticial Modeling Based on Generalized Linear Models, 2nd ed. (Springer, p. 60), where they compare "log-linear model fits to cellular differentiation data based on quasi-likelihoods" between variance = phi*mu (quasi-Poisson), variance = phi*mu^2 (quas...

Dear R users, I am trying to fit a glm with a distribution free family, link = log and variance = constant*mu. I guess I have to use the quasi family but the choices of variance are restricted to constant or mu or mu^2..., I don't know the way to choose the variance that I need, i.e. constant*mu. If you have any ideas or advice, please tell me. Thanks, Laetitia Mestdagh Laetitia Mestdagh

Buenas. Sé que en R hay multitud de datasets y me haría falta alguno que trataran de variables relacionadas con salud, sobre todo para aprender más acerca de cómo realizar una regresión logística binomial o multinomial. Gracias..

If you mean this paper by Fahrmeir: http://biomet.oxfordjournals.org/cgi/content/abstract/81/2/317 I would recommend BayesX: http://www.stat.uni-muenchen.de/~bayesx/. BayesX interfaces with R and estimates discrete (and continuous) time survival data with penalized regression methods. If you are looking for a bona fide Bayesian sur...

...ASS::loglm(), using R Under development (unstable) (2013-09-11 r63906) > Caesar.mod0 <- loglm(~Infection + (Risk*Antibiotics*Planned), data=Caesar) Error: could not find function "loglm" In DESCRIPTION I have Depends: R (>= 2.10), vcd, gnm (>= 1.0.3) Suggests: ca,gmodels,Fahrmeir,effects,VGAM,plyr,rgl,lmtest,MASS,nnet,ggplot2,Sleuth2,car and the vcd DESCRIPTION has Depends: R (>= 2.4.0), grid, stats Suggests: KernSmooth, mvtnorm, kernlab, HSAUR, coin Imports: utils, MASS, grDevices, colorspace so, in an R 3.0.0 console, library(vcdExtra) loads vcd and its dependencies...

...ith the exception that in the former one has individual data and in the latter one aggregated data. The difference between the two examples is on a single subject: I substituted to the first example a censored case with a subject who died at the first time-unit. Afterward I fitted a logistic model (Fahrmeir and Tutz, 2001) in the glm context, but whereas there is not difference between individual and aggregated dataset in the first example, I noted some discrepancies in the second example. I might guess that something with weights is going on, but I did not manage to clearly understand. Hope that the...

Dear R-listers, I am working with generalized linear mixed models to quantify the variance due to two nested random factors, but have hit a snag in the interpretation of variance components. Despite my best efforts with Venables & Ripley 2002, Fahrmeir & Tutz 2001, R-help archives, Google, and other eminent sources (i.e. local R gurus), I have not been able to find a definitive answer explaining when the value reported for the residual error represents a scale parameter, and when it represents the actual variance (or standard error) and can b...

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CRAN (and crantastic) updates this week New packages ------------ * EffectStars (1.0) Maintainer: Unknown Author(s): Gunther Schauberger License: GPL-2 http://crantastic.org/packages/EffectStars The package provides functions to visualize regression models with categorical response. The effects of the covariates are plotted with star plots in order to allow for an optical